CVE-2026-42899: ASP.NET Core Denial of Service Vulnerability

Overview

Severity

High (CVSS 7.5)

CVSS Vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C

Category

Denial of Service

Exploit Status

Not Exploited

Exploitation Likelihood

Unlikely

Patch Tuesday

2026-May

Released

2026-05-12

Description

Loop with unreachable exit condition ('infinite loop') in ASP.NET Core allows an unauthorized attacker to deny service over a network.

Affected Products (9)

Developer Tools

• .NET 8.0 installed on Windows
• .NET 9.0 installed on Linux
• .NET 8.0 installed on Mac OS
• .NET 8.0 installed on Linux
• .NET 9.0 installed on Windows
• .NET 9.0 installed on Mac OS
• .NET 10.0 installed on Mac OS
• .NET 10.0 installed on Linux
• .NET 10.0 installed on Windows

Security Updates (3)

• 5093447
• 5093448
• 5093446

Acknowledgments

hamayanhamayan, <a href="https://www.linkedin.com/in/abdul-rehman---/">Muhammad Abdul Rehman</a>

Revision History

• 2026-05-12: Information published.